In the field of vehicles, for example cars, the different seats for the driver and the passengers, respectively, are normally provided with headrests. A general requirement is that the headrest should be arranged adjacent to the occupant's head so as to provide support for the neck during driving, since the occupant is normally leaning back. Furthermore, a purpose with such a headrest is to provide protection in the event of a collision.
Fixed (i.e. non-adjustable) headrests are common in today's vehicles. Although a headrest of this type normally provides good support and protection for the head of the occupant, its effect is somewhat limited since it does not provide equally high comfort and protection for all occupants. This is of course due to the fact that different occupants have different body shapes and driving positions. This problem can be solved by means of a headrest which comprises an adjustment mechanism, so that the headrest can be inclined and positioned in different angular positions in relation to the occupant's seat, i.e. in relation to the seat's backrest.
A number of different types of such adjustable headrests are previously known. One Solution is based on the principle that only frictional force is used to lock the headrest in the desired position in relation to the backrest of the vehicle seat. Furthermore, mechanisms are also known by means of which the headrest can be swung back and forth between a plurality of positions, step by step towards an end position, and wherein further tilting results in the headrest resuming its initial position so that adjustment can be carried out again. Furthermore, solutions comprising electrical adjustment of the headrest and which also may comprise a memory are previously known.
Although the previously known adjustable headrests function in an acceptable manner in most situations, they imply certain problems. Firstly, they do allow adjustment of the headrest by using one hand only, which is required from a comfort point of view of the occupant and which also is an advantage as regards safety, since the driver cannot remove both hands from the steering wheel while driving the vehicle. Another problem associated with the previously known solutions relates to the fact that they cannot normally hold the headrest in the assumed position in case of a collision or during sudden acceleration or deceleration. Naturally, this may lead to personal injuries. Furthermore, the known solution which comprises an electrical adjustment mechanism involves a disadvantage, i.e. it is too expensive to manufacture and unnecessarily complicated.